Linux: Use After Free
CVE-2023-53432 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 2ea70379e4f4efa95c9daa7f3f9bdd4d40aec927, 9040adc38cf6bfbb77034d558ac2c52f70d840ac, 9860921ab4521252dc39bb21b9c936bd09a00982 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.21% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 2ea70379e4f4efa95c9daa7f3f9bdd4d40aec927 or 9040adc38cf6bfbb77034d558ac2c52f70d840ac or 9860921ab4521252dc39bb21b9c936bd09a00982 or 3ff256751a2853e1ffaa36958ff933ccc98c6cb5, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.128 or 6.1.47 or 6.4.12, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | c76acec6d55107b652a37c90b36c00bc8b04dabb up to, but not including, 2ea70379e4f4efa95c9daa7f3f9bdd4d40aec927; c76acec6d55107b652a37c90b36c00bc8b04dabb up to, but not including, 9040adc38cf6bfbb77034d558ac2c52f70d840ac; c76acec6d55107b652a37c90b36c00bc8b04dabb up to, but not including, 9860921ab4521252dc39bb21b9c936bd09a00982; c76acec6d55107b652a37c90b36c00bc8b04dabb up to, but not including, 3ff256751a2853e1ffaa36958ff933ccc98c6cb5; 2.6.31 | 2ea70379e4f4efa95c9daa7f3f9bdd4d40aec927, 9040adc38cf6bfbb77034d558ac2c52f70d840ac, 9860921ab4521252dc39bb21b9c936bd09a00982, 3ff256751a2853e1ffaa36958ff933ccc98c6cb5 |
| Linux | Linux Kernel | before 5.15.128; 5.16 up to, but not including, 6.1.47; 6.2 up to, but not including, 6.4.12 | 5.15.128, 6.1.47, 6.4.12 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: firewire: net: fix use after free in fwnet_finish_incoming_packet() The netif_rx() function frees the skb so we can't dereference it to save the skb->len.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Use After Free vulnerabilities
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